1. Field
Embodiments relate to a secondary battery and a secondary battery module.
2. Description of the Related Art
A secondary battery may be repeatedly discharged and recharged unlike a primary battery that may not be rechargeable. A secondary battery may be economical and may be environmentally friendly.
A secondary battery may be used as a single battery or a plurality of unit secondary batteries may be used as a unit, that is, a battery module may be used according to a kind of external devices to which the secondary battery will be applied.